The single chip microcomputer adds a PCF8574 module to realize the IIC mode to drive LCD1602

The PCF8574 module makes it possible to realize IIC driving LCD1602.

The following figure is the connection circuit diagram of PCF8574 module and 1602:

The actual connection method is as follows:

If you want to use the PCF8574 module to implement IIC driving LCD1602, it is very necessary to first understand the timing of IIC, PCF8574 device address, and four-line control LCD1602 method.

Below are two important h files. You can transplant them into your program by modifying some codes in these two h files (the wiring is different).

The microcontroller source program is as follows:

void delay1(uchar x)

{

        uchar a,b;

        for(a=x;a>0;a--)

         for(b=200;b>0;b--);

}

void write_com(uchar com) //write command function

{ uchar com1,com2;

        com1=com|0x0f;

        write_add(com1&0xfc);

        delay1(2);

    write_add(com1&0xf8);

        com2=com<<4;

        com2=com2|0x0f;

        write_add(com2&0xfc);

        delay1(2);

    write_add(com2&0xf8);

}

void write_date(uchar date) //Write data function

{

        uchar date1,date2;

        date1=date|0x0f;

        write_add(date1&0xfd);

        delay1(2);

        write_add(date1&0xf9);

        date2=date<<4;

        date2=date2|0x0f;

        write_add(date2&0xfd);

        delay1(2);

        write_add(date2&0xf9);

}

void init_lcd() //initialization function

{                                                                                                  

        write_com(0x33); //Display mode setting

        delayms(6);

        write_com(0x32); //Display mode setting

        delayms(6);

        write_com(0x28); //4-bit bus, double-line display, display 5×7 dot matrix characters

        delayms(6);

        write_com(0x01); //Clear screen

        delayms(6);

        write_com(0x06); //Character entry mode: screen does not move, characters move backward

        delayms(6);

        write_com(0x0c); //Display on and off cursor

        //write_LCD_Command(0x0f); //display on, cursor on, cursor blinking

        delayms(6);

}

//Display string: what is displayed in row x, column y

void ShowString(unsigned char x,unsigned char y,unsigned char *str)

{

        if(x == 1)

        {

                write_com(0x80 | y-1); 

        }

        if(x == 2)

        {

                write_com(0xc0 | y-1);

        }

        // Output string

        while(*str!='')

        {

                write_date(*str);

                str++;

        }

}